Description: 2m/70cm dual band, high performance, radialless mobile, gain whip antenna. Offers 5.0dB gain on 144 MHz and 7.6dB gain on 70cm. The antenna is a 5/8 wave on 70 and 7/8 on 2 and handles up to 150 watts.

and it is still going strong, and built like a rock. Many knock downs when used w/magnetic mount on the top of old Trooper.
I just can't believe the (almost 1/2") spring loaded stub slides up and out of the base of the antenna and folds back on its own. Even tree branch knock downs didn't do that. You can't drive fast enough to create that much wind force required to pull off that trick........

The spring loaded break-over design will not stay up at highway speeds after a couple of months. These antennas looked promising, as they seem to function well. But the mechanical design is lacking. This is the second Diamond I've bought. I had a SG7900 previously. The same problem with the spring loaded break over happened to the SGC7900. So this will probably be the last Diamond product I buy. Also see my review on the K9000 motorized mount.

I've been using the orginal SG-7500 (non "a" model) for nearly 15 years with exceptional results! I bought the antenna and Diamond's K600M trunk lip mount in 1992. At that time it was for use with my Kenwood TH-78a HT, and a few years later the Kenwood TH-F6a. The antenna is now on Diamond's K900M Motorized Mount (Luggage Rack version)on my SUV and connected to my Kenwood TM-742AD (2m/220/440).

It has always worked great! Even though years ago some stupid drunkard bent the whip 90į just above the base coil (with Dwayne's reassurance at Diamond Antennas) I straighed the whip and it continues to perform wonderfully.

I have the NMO version of this antenna, no differance between the two other than the mount. I'm very pleased with it. One note, whoever wrote the specs, at the top of the page, was way out of it. Per Diamond's site: http://www.diamondantenna.net/sg7500a.html
the gain is 3.5 for 2 meters and 6.0 for 70cm, not the heavily bloated figures stated stated above, and these are in dBi not dBd.

Here in Rochester, NY where ice storms, and road salt take there toll on everything, the SG7500A is working well! I'm using the Diamond K600M trunk lip mount, which is all stainless steel (not like the cheap'o Larsen which rusted in one season). I've had excellent performance on both bands, the SWR is reasonable, and mechanically the unit is working fine. I've removed it (SO-239 screw on base) lots of times to go through the car wash and there is no sign of water penetration, mildew, or discoloration inside either the antenna or mount.

Another installation bonus of the K600M is the PL-259's outer ring unscrews from the cable so you can feed it through those tight places in a mobile installation. Nice touch. The coax lead from the K600M is a short (9 inches) piece of RG-174 that gets pinched where the trunk's rubber seal touches the trunk lid. They provide a small rubber "bumper" to help protect the RG-174 at the point the trunk's seal and trunk lid mate. Works great!

I have just purchased a SG7500 dualband antenna, but the base says that it is a Reuex RA 7500, are these the same antenna, or has the product been switched in the packaging before I bought it. I do not want to install untill I have some good information please.
Purchased on 19th November 2003

While at a hamfest, I traded a Larsen Radiall for this antenna. I like its looks, and its performance, (although I do think its listed gain figures are bit hyped). But the things that bother me about this antenna are its crappy mag mount for the UHF type connector and the fact that it has so many joints and Allen screws that become loose; thus the antenna begins to rattle.

One criticism at a time: The mag mount for this big antenna is weak and much too small to handle its weight and height. I have had the living hell scared out of me on the highway when this magnet gives up its hold of my truck's roof. Big rigs passing you on the open road will make the antenna sway BADLY and the magnet will give up its hold and the resulting noise (if not the damage from this thing flying off your roof)will age you. Stopping to re-mount this thing has gotten old... FAST.

Criticism Two: Due to it's construction and engineering, the antenna is a multi-jointed, multi-load jobber that does NOT fold over for garage storage. Add to the fact that Allen screws are used to fasten said loads and joints together. Let's see... BAD wind performance, multi-parts, and a weak base make for this antenna taking a beating and falling apart (sooner or later). After a year with this thing, I've re-tightened several of the Allen screws and re-set the loads on the element. Although it cost me nothing, I'm sad to say that although it looks good mounted and it's performance is so-so, it's continuing need for maintenance and re-setting on the roof after flying off, have left this operator remaining loyal to the Comet SBB5-NMO reviewed elsewhere here.

As always, The very best of 73!

Luis KD5KJD

P.S. The magnet just came off and out from its housing this morning on the way to work. It happened just before I was to start our morning mobile roundtable QSO. Luckily, the tool box has a wire brush and some JB Weld. I know how my lunch hour is going to be spent....

This antenna is awesome. Allot of the repeaters that I like are far and/or have poor line of site from where I live. My route to work is also on the "fringe" of the repeaters. That fringe has greatly improved since I started using this antenna.

However, if you buy this antenna you naturally have to buy a mount for it as well. The mounts are almost as much $ as the antenna itself !

I started off using the SG7500 (about $80) with a K600M trunk mount (about $60). I was very happy with this set-up for a year and a half. The K600M mount has plenty of cable to run from the trunk of the largest cars all the way to the radio in the front. It mounts on the "lip" of the trunk so that you donít have to cut a hole in your vehicle.

Recently, I got a new SUV. Now I have a $60 mount (K600M) that I cant use and I had to get a $70 K400C mount for the SUV. On top of that, the K400C uses a very short section of cable and its so thin I call it "string coax". This cable is only about 4 or 5 feet long. I had to attach a section of "real" cable to the end of the "string coax" for it to reach my radio! On the plus side, once this mount is secured to any "lip", such as the edge of a vehicle door, it can be positioned in any position. I have mine attached to the top of my rear passenger door close to the hinge end of the door.

In short, I would give the antenna a rating of 5 but since you need to get a mount I had to take the mounts into consideration. So, I will give a rating of 4 overall because of the K400C mount. The antenna rocks and the K600M mount is very cool. But, stay away from the K400C mount if you can.

73 de KB1HGI
John

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